Your comments

OK, I never used TextEdit for anything but nothing. ;) It's still inconvenient though.

Same here. It definitely should not remove any BOM without even asking the user.

But you are not going to share these improvements with us during the current decade?

I think this is the better approach. A good editor should stay an editor and not transform into an IDE.

Unfortunately there have been no updates to Textastic for Mac since January 2017. Are you still working on it or have an ETA?